Abstract: Systems and methods are provided for providing a consistent experience for users of cloud-based block storage volumes. While cloud storage aims to remove hardware considerations for an end user's experience, block storage performance can nevertheless vary according to the underlying hardware used to support a volume or the specific network location of that hardware. Embodiments of the present disclosure address that inconsistent performance by associating a volume with a performance profile that sets a target latency for the volume. A storage client can then monitor observed latency for the volume and inject synthetic latency into input/output operations for the volume as calculated via a proportional-integral-derivative algorithm, such that the observed latency matches the target within the performance profile. This enables the cloud provider to vary physical hardware or network configurations without effect on block storage performance from the point of view of an end user.

Abstract: A drive system for an aircraft includes a first gearbox assembly and a second gearbox assembly that is in mechanical communication with the first gearbox assembly. A first pressurized lubrication system is configured to circulate a first lubricant through the first gearbox assembly. A second pressurized lubrication system is configured to circulate a second lubricant through the second gearbox assembly. An emergency lubrication system is configured to autonomously supply a portion of the first lubricant to the second gearbox assembly responsive to a loss of pressure in the second pressurized lubrication system. The emergency lubrication system is also configured to autonomously supply a portion of the second lubricant to the first gearbox assembly responsive to a loss of pressure in the first pressurized lubrication system.

Abstract: Systems and methods are provided for handling file operations from a hosted computing instance via a secure compute layer. The secure compute layer is presented to the instance as a virtualized service device that is locally addressable by the instance. Software within the instance can submit file operations to the virtualized service device, which the secure compute layer can translate into calls to a network-accessible storage service. Results from the calls can then be passed back to the instance through the virtualized service device. As a result, the instance can communicate with a variety of different network services, without itself implementing network communications for those services.

Abstract: A drive system has a gearbox, comprising a passage therethrough, a coupling shaft disposed at least partially within the passage and a first coupling carried by a first end of the coupling shaft. The first coupling is configured to accommodate misalignment. The drive system also has a second coupling carried by a second end of the coupling shaft. The second coupling is also configured to accommodate misalignment.

Abstract: A tail rotor isolation system for rotorcraft includes a secondary engine, first and second freewheeling units, an isolation assembly and a tail rotor system. The secondary engine is coupled to the input race of the first freewheeling unit. A main rotor system is coupled to the output race of the second freewheeling unit. The isolation assembly is coupled to the output race of the first freewheeling unit and has a fully engaged position coupling the input and output races of the second freewheeling unit and a partially engaged position coupled to the input race but decoupled from the output race of the second freewheeling unit. The tail rotor system is coupled to the input race of the second freewheeling unit such that in the partially engaged position of the isolation assembly, the overrunning mode of the second freewheeling unit isolates the tail rotor system from the main rotor system.

Abstract: A bearing raceway for a shaft includes a tubular sleeve comprising a raceway section and a clamp section, the raceway section having a hardened outer surface and a first, axially linear, inner surface, and the clamp section having first threads and a second, axially non-linear, inner surface, where the first threads are configured to mate with second threads on a nut to clamp the tubular sleeve to the shaft.

Abstract: A drive system for an aircraft includes a first gearbox assembly and a second gearbox assembly that is in mechanical communication with the first gearbox assembly. A first pressurized lubrication system is configured to circulate a first lubricant through the first gearbox assembly. A second pressurized lubrication system is configured to circulate a second lubricant through the second gearbox assembly. An emergency lubrication system is configured to autonomously supply a portion of the first lubricant to the second gearbox assembly responsive to a loss of pressure in the second pressurized lubrication system. The emergency lubrication system is also configured to autonomously supply a portion of the second lubricant to the first gearbox assembly responsive to a loss of pressure in the first pressurized lubrication system.

Abstract: Systems and methods are provided for implementing a multi-service file system for a hosted computing instance via a locally-addressable secure compute layer. Software within the instance can submit file operations to the secure compute layer, which the secure compute layer can translate into calls to one or more network-accessible storage services. To provide a multi-service file system, the secure compute layer can obtain mapping data mapping file system objects within the virtualized file system to different network-accessible storage services. On receiving a file operation, the secure compute layer can determine one or more network-accessible storage services corresponding to the file operation, and submit appropriate calls to the one or more network-accessible storage services.

Abstract: A bearing raceway for a shaft includes a tubular sleeve comprising a raceway section and a clamp section, the raceway section having a hardened outer surface and a first, axially linear, inner surface, and the clamp section having first threads and a second, axially non-linear, inner surface, where the first threads are configured to mate with second threads on a nut to clamp the tubular sleeve to the shaft.

Abstract: A system includes a chip detector that includes a magnet, the chip detector operable to collect a plurality of chips in a lubricant flow. The system also includes a radiation sensor associated with the magnet and operable to detect radiation emitted by at least some of the plurality of chips collected by the magnet.

Abstract: An exemplary passive oil system includes a reservoir housing configured in operation to rotate around a rotational axis, the reservoir housing defining a reservoir between a top wall, a bottom wall, innermost side, and an outer sidewall; and an outlet positioned adjacent the outer sidewall to discharge a lubrication fluid contained in the reservoir in response to the reservoir housing rotating around the rotational axis.

Abstract: A multimode clutch assembly is positioned in a powertrain of a rotorcraft. The clutch assembly includes a freewheeling unit having a driving mode in which torque applied to the input race is transferred to the output race and an overrunning mode in which torque applied to the output race is not transferred to the input race. A bypass assembly has an engaged position that couples the input and output races of the freewheeling unit. An actuator assembly shifts the bypass assembly between engaged and disengaged positions. An engagement status sensor is configured to determine the engagement status of the bypass assembly. In the disengaged position, the overrunning mode of the freewheeling unit is enabled such that the clutch assembly is configured for unidirectional torque transfer. In the engaged position, the overrunning mode of the freewheeling unit is disabled such that the clutch assembly is configured for bidirectional torque transfer.

Abstract: A failsafe multimode clutch assembly positioned in a powertrain of a rotorcraft. The clutch assembly includes a freewheeling having a driving mode in which torque applied to the input race is transferred to the output race and an overrunning mode in which torque applied to the output race is not transferred to the input race. A bypass assembly has an engaged position that couples the input and output races of the freewheeling unit. An actuator assembly uses pressurized lubricating oil to shift the bypass assembly between the engaged position and a disengaged position. A lock assembly enables and disables actuation of the bypass assembly. In the disengaged position, the overrunning mode of the freewheeling unit enables a unidirectional torque transfer mode of the clutch assembly. In the engaged position, the overrunning mode of the freewheeling unit is disabled such that the clutch assembly is configured for bidirectional torque transfer.

Abstract: A tail rotor isolation system for rotorcraft includes a secondary engine, first and second freewheeling units, an isolation assembly and a tail rotor system. The secondary engine is coupled to the input race of the first freewheeling unit. A main rotor system is coupled to the output race of the second freewheeling unit. The isolation assembly is coupled to the output race of the first freewheeling unit and has a fully engaged position coupling the input and output races of the second freewheeling unit and a partially engaged position coupled to the input race but decoupled from the output race of the second freewheeling unit. The tail rotor system is coupled to the input race of the second freewheeling unit such that in the partially engaged position of the isolation assembly, the overrunning mode of the second freewheeling unit isolates the tail rotor system from the main rotor system.

Abstract: Systems and methods include providing an aircraft with a fuselage and a wing assembly rotatable relative to the fuselage about a stow axis between a flight position and a stowed position. The aircraft includes an engine reduction gearbox having a retractable driveshaft that selectively engages the mid-wing gearbox via axially translatable motion along a rotation axis when the wing assembly is in the flight position. The mid-wing gearbox includes a plunger seal that is displaced in response to contact with the retractable driveshaft. Displacement of the plunger seal allows lubricant to flow through an inner bore in the retractable driveshaft, across splines of the retractable driveshaft and the mid-wing gearbox, and through lubrication ports in the mid-wing gearbox to lubricate the engine reduction gearbox, splines of the retractable driveshaft and the mid-wing gearbox, and the mid-wing gearbox via a single lubrication system.

Abstract: Systems and methods for efficient and secure management of encrypted “snapshots” for a remote provider substrate extension (“PSE”) of a cloud provider network substrate are provided. The PSE may request and obtain a snapshot from the cloud provider network substrate, restore a volume from the snapshot, make changes to data in the restored volume, and/or initiate the creation and storage of a new snapshot that includes incremental updates to the original snapshot to reflect the changes made to data in the volume. An encrypted snapshot stored within the cloud provider network substrate may be decrypted using a cloud provider key designed for internal use only, and then re-encrypted using a PSE-specific key before providing the snapshot to the PSE, thereby avoiding the sharing of the cloud provider internal use only key outside the cloud provider network substrate.

Abstract: A first block storage server virtual machine to host a first volume using one or more storage devices of a computer system is executed by the computer system. A second virtual machine having access to a virtual block storage device is executed by the computer system. A block storage client is executed by the computer system. A first block storage operation is received by the block storage client from the second virtual machine, the first block storage operation to perform on the virtual block storage device. A message is sent by the block storage client to the first block storage server virtual machine to cause the first block storage server virtual machine to perform the block storage operation with the first volume.

Abstract: One or more configuration parameters for an object gateway instance are received at an interface to a provider network, the parameters including an identifier of a first object store of the provider network for which to cache objects in a first object cache of the object gateway instance and an indication of a data transfer mode that controls when objects written to the first object cache are written to the first object store. The one or more configuration parameters are stored in a data store of the provider network and sent to the object gateway instance. A read request that includes the identifier of the first object store and a first object identifier is received from the object gateway instance, and a first object associated with the first object identifier and stored in the first object store is sent to the object gateway instance.

Abstract: A data storage manager may manage storage locations for blocks of a storage volume. The blocks of the storage volume may be assigned to a logical volume exposed to a computing instance supported by a host. Furthermore, the data storage manager may also generate and maintain a set of rules that specify the locations of blocks of the storage volume, and provides the set of rules to the host. The set of rules may be included in a data structure enabling the host to access the blocks based at least in part on the information included in the set of rules.

Abstract: Security can be provided for data stored using resources that are deployed in an environment managed by a third party. Physical and logical detection mechanisms can be used to monitor various security aspects, and the resulting security data can be used to identify potential threats to these resources. In some embodiments, suspicious activity can cause resources such as data servers to be automatically and remotely rebooted such that keys stored in volatile memory on those data servers will be lost from those servers, such that an attacker will be unable to decrypt data stored on those servers. Once a determination of safety is made, the keys can be provided to the respective data servers such that data operations can resume.